As reliance on computer systems and the internet increases in many areas such as personal communications, shopping, banking, commerce, etc., the need for improved cyber security also increases. Many security measures may be employed, including cryptography. A physical unclonable function (PUF) is a physical object embodied in a physical structure that can be used to produce an output. The output is easy to evaluate but the output is very hard or nearly impossible to predict. A PUF can be used as a unique identification or key in secure computing and communication.
An individual PUF device must be easy to make but practically impossible to duplicate, even given the exact manufacturing process that produced it. In this respect it is the hardware analog of a one-way function. PUFs are typically implemented in integrated circuits and are typically used in applications with high security requirements.